Motion activated Super Mario thingy

We all remember good old Mario Bros game. Well, some of us still play it! John obviously can't get enough of it so he made a desk adornment in Mario Brothers mushroom candy tin in which he placed microcontroller, two LEDs, motion detector and a speaker.

After detecting the motion, mushroom device activates and starts playing Mario Bros game theme with LED blinking effect. Micocontroller used in this application is Attiny13A, motion detector is PIR sensor and it is all powered from USB port. What's interesting here is audio theme reproduction from microcontroller and that part is nicely described. Source code is available for download on project page.